Cylindrical lithium ion battery structure

Abstract

The utility model relates to a lithium ion battery, in particular to a cylindrical lithium ion battery structure, which is characterized in that a positive pole piece, an isolating layer and a negative pole piece are wound to form a roll core assembly, at least one tab area is arranged on the upper edge of the positive pole piece, at least one tab is arranged in the tab area through a die cutting process, and when the roll core assembly is formed by winding, the tab area is not damaged. The tab areas are overlapped, the tabs of the tab areas are respectively and correspondingly overlapped, the positive current collecting disc is connected with the tabs of the positive pole pieces, a central hole in the positive current collecting disc is staggered with the positive pole pieces, and the positive pole end of the battery adopts a form of overlapping a plurality of tabs, so that metal scraps are reduced, seepage and air passages are improved, and the safety performance of the battery is improved.

Description

Technical Field

[0001] This utility model relates to lithium-ion batteries, specifically to a cylindrical lithium-ion battery structure. Background Technology

[0002] Due to its structural characteristics, the all-tab cylindrical lithium-ion battery has an 80% lower internal resistance compared to conventional structures, generates less heat, and significantly improves cycle life and power characteristics, making it a major future development trend. Currently, most all-tab cells are manufactured using a mechanical flattening method. While this technology is relatively mature and the process is relatively simple, the mechanical flattening process generates metal debris, especially at the positive tab end. Due to the material properties of aluminum, controlling aluminum debris is more difficult, and it can easily be introduced into the core, significantly impacting battery safety. Furthermore, the accumulation of metal at the flattened end face can block the cell's air passages, affecting leakage and gas discharge, thus impacting cell performance. Utility Model Content

[0003] The technical problem to be solved by this utility model is to provide a cylindrical lithium-ion battery structure that improves the positive terminal of the battery, solves the problem of metal shavings entering the core, improves the problem of cell leakage and air passage, combines the advantages of flattened structure and multi-tab structure, controls manufacturing cost, and improves cell safety.

[0004] To solve the above-mentioned technical problems, the technical solution adopted by this utility model is as follows: a cylindrical lithium-ion battery structure, including a positive electrode sheet, a negative electrode sheet, an separator layer, and a positive current collector. The separator layer is disposed between the positive and negative electrode sheets. The positive electrode sheet, separator layer, and negative electrode sheet are wound to form a core assembly. At least one tab area is provided on the upper edge of the positive electrode sheet, and at least one tab is provided in the tab area. When the core assembly is wound, the tab areas overlap and the tabs in each tab area overlap correspondingly. The positive current collector is connected to each tab of the positive electrode sheet, and the central hole on the positive current collector is misaligned with each positive electrode sheet. The positive terminal of the battery adopts multiple overlapping tabs to reduce metal debris, improve leakage and gas passages, and improve the safety performance of the battery.

[0005] As an optional solution, the upper edge of the positive electrode sheet does not have tab areas at the innermost and outermost rings of the corresponding core assembly. The core assembly does not have tab areas at the innermost ring to avoid the tabs affecting the unobstructed flow of the central hole, and it also does not have tab areas at the outermost ring to avoid damage to the tabs.

[0006] As an optional solution, four tabs are provided on each tab area of ​​the positive electrode plate, and four tab connection areas are provided on the positive current collector. The four tabs of each tab area are respectively connected to the four tab connection areas of the positive current collector.

[0007] As an optional scheme, the four tabs in each tab region are evenly distributed along the upper edge of the positive electrode plate, and four tab connection areas are evenly arranged circumferentially along the upper edge of the positive current collector, with a cap connection area provided at one of the tab connection areas.

[0008] As an optional solution, the tabs are laser-welded to the positive current collector.

[0009] Based on the same concept, this utility model also provides a cylindrical lithium-ion battery structure, including a positive electrode, a negative electrode, a separator, and a cap. The separator is disposed between the positive electrode and the negative electrode. The positive electrode, the separator, and the negative electrode are wound together to form a core assembly. At least two tabs are provided on the upper edge of the positive electrode. Each tab is welded together and connected to the cap.

[0010] Compared with the prior art, the advantages of this utility model are as follows: The lithium battery structure of this utility model adopts multiple overlapping tabs at the positive end, which not only reduces the safety risks caused by metal debris, but also improves the problems of electrolyte leakage and air passage, thus improving the safety performance of the battery; moreover, the electrode tabs are processed by die-cutting process, which improves the unevenness of the cell welding platform, reduces the risk of poor welding and burn-through, and improves the problems of electrolyte leakage and air passage. Attached Figure Description

[0011] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0012] Figure 1 This is a schematic diagram showing the distribution of each tab region and tab when the positive electrode sheet is in the unfolded state in Example 1;

[0013] Figure 2 This is a schematic diagram of the positive current collector in Example 1;

[0014] Figure 3 This is a schematic diagram showing the connection between the positive current collector and the winding core assembly in Example 1;

[0015] Figure 4 This is a schematic diagram showing the distribution of each tab in the unfolded state of the positive electrode plate in Example 2;

[0016] Figure 5 This is a schematic diagram showing the unfolded negative electrode sheet in Examples 1 and 2;

[0017] In the diagram: 1. Positive electrode plate, 11. Tab area, 111. Tab, 2. Negative electrode plate, 3. Positive current collector, 31. Tab connection area, 32. Cap connection area, 4. Core assembly. Detailed Implementation

[0018] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0019] Example 1

[0020] Please see Figures 1-3 as well as Figure 5 A cylindrical lithium-ion battery structure includes a positive electrode 1, a negative electrode 2, an separator layer, and a positive current collector 3. Similar to existing lithium-ion batteries, the separator layer is placed between the positive electrode 1 and the negative electrode 2. The composite structure formed by the positive electrode 1, the separator layer, and the negative electrode 2 is then wound to form the battery core assembly 4.

[0021] Please see Figure 1 The upper edge of the positive electrode 1 refers to the edge of the positive electrode corresponding to the positive electrode of the core assembly 4. The upper edge of the positive electrode 1 is provided with at least one tab region 11. At least one tab 111 is provided at each tab region 11. When the positive electrode 1, the insulating layer and the negative electrode 2 are wound to form the core assembly 4, from the inner circle to the outer circle of the core assembly 4, each layer of tab regions 11 overlaps accordingly. Each tab 111 of each layer of tab region 11 overlaps with each tab 111 of another tab region 11. Figure 1 In the diagram, L1, L2 to LN refer to the tab areas 11 on the positive electrode 1, from the inner ring to the outer ring of the core assembly 4. The positive current collector 3 is located at the positive end of the core assembly 4. The positive current collector 3 is connected to each tab 111 of the positive electrode 1. The center holes of each positive electrode 1 and the positive current collector 3 are staggered to avoid clogging the center holes.

[0022] As a further implementation, no tab area 11 is provided at the upper edge of the positive electrode sheet 1 at the innermost and outermost rings of the corresponding core assembly 4. The absence of tab area 11 at the innermost ring of the corresponding core assembly 4 can further ensure that the center hole is unobstructed, and the absence of tab area 11 at the outermost ring of the corresponding core assembly 4 can prevent damage to the outer edge of the core assembly 4, thereby avoiding safety accidents.

[0023] In a preferred embodiment, each tab region 11 of the positive electrode sheet 1 corresponds to one ring of the winding core assembly 4, and the length of the tab region 11 gradually increases from the inner ring to the outer ring of the winding core assembly 4. Four tabs are provided on each tab region 11 of the positive electrode sheet 1: a first tab, a second tab, a third tab, and a fourth tab. Four tab connection regions 31 are provided on the positive electrode current collector 3: a first tab connection region 31, a second tab connection region 31, a third tab connection region 31, and a fourth tab connection region 31. In each tab region 11 of the positive electrode sheet 1, the first tab is connected to the first connection region, the second tab is connected to the second connection region, the third tab is connected to the third connection region, and the fourth tab is connected to the fourth connection region. Each tab 111 is laser-welded to the positive electrode current collector 3.

[0024] For further details, please refer to Figure 2 and Figure 3 The four tabs 111 of each tab region 11 are evenly distributed along the upper edge of the positive electrode sheet 1. When the core assembly 4 is wound, the four positive electrode sheets 1 of each tab region 11 are evenly distributed circumferentially. Four tab connection areas 31 are evenly arranged circumferentially along the upper edge of the positive current collector 3, and the positive current collector 3 has a cross-shaped structure. A cap connection area 32 is also provided at one of the tab connection areas 31, and a bending-friendly area is provided between the cap connection area 32 and the tab connection area 31.

[0025] In some embodiments, the positive electrode 1 is made in the following manner: the positive electrode 1 is continuously coated without segmentation in the middle, the upper end of the electrode is not coated with positive electrode material, a cutting area is reserved, and a die-cutting process is used to cut off the innermost and outermost parts of the cutting area. The remaining part of the cutting area is divided into multiple tab areas 11, and then each tab area 11 is cut to form tabs.

[0026] Please see Figure 5 The lower end of the negative electrode sheet 2 is reserved for the electrode tab processing area. After the core assembly 4 is wound, the lower end of the negative electrode sheet 2 is flattened to form a flattened electrode tab structure.

[0027] Example 2

[0028] A cylindrical lithium-ion battery structure includes a positive electrode 1, a negative electrode 2, a separator layer, and a cap. The separator layer is disposed between the positive electrode 1 and the negative electrode 2. The positive electrode 1, the separator layer, and the negative electrode 2 are wound together to form a core assembly 4. (See also...) Figure 4 The positive electrode 1 has at least two tabs along its upper edge. After the tabs are welded together, they are connected to the cap. Preferably, after the core assembly 4 is wound, the tabs overlap face-to-face. The negative electrode 2 is the same as the negative electrode 2 in Embodiment 1, and the tab structure is formed by a flattening operation.

[0029] In this embodiment, the number of tabs 111 on the positive electrode 1 can be adjusted according to the production process and actual power requirements. The greater the power requirements, the more tabs are required.

[0030] In this specification, the terms "an embodiment," "example," "specific example," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0031] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A cylindrical lithium ion battery structure comprising a positive electrode sheet (1), a negative electrode sheet (2), a separator layer, and a positive electrode current collector (3), the separator layer being provided between the positive electrode sheet (1) and the negative electrode sheet (2), the positive electrode sheet (1), the separator layer, and the negative electrode sheet (2) being wound to form a core assembly (4), characterized in that: The upper edge of the positive electrode plate (1) is provided with at least one tab area (11), and the tab area (11) is provided with at least one tab (111). When the core assembly (4) is wound, each tab area (11) is overlapped, and the tabs (111) of each tab area (11) are respectively correspondingly overlapped. The positive current collector disc (3) is connected with each tab of the positive electrode plate (1), and the center hole on the positive current collector disc (3) is dislocated with each positive electrode plate (1).

2. The cylindrical lithium-ion battery structure of claim 1, wherein: The upper edge of the positive electrode plate (1) is not provided with a tab area (11) at the position corresponding to the innermost circle and the outermost circle of the core assembly (4).

3. The cylindrical lithium-ion battery structure of claim 2, wherein: Four tabs (111) are arranged on the positive electrode plate (1) at each tab area (11), and four tab connecting areas (31) are arranged on the positive current collector disc (3). The four tabs (111) of each tab area (11) are respectively connected with the four tab connecting areas (31) of the positive current collector disc (3).

4. The cylindrical lithium-ion battery structure of claim 3, wherein: The four tabs (111) of each tab area (11) are equally spaced along the upper edge of the positive electrode plate (1), and the four tab connecting areas (31) are uniformly arranged on the upper edge of the positive current collector disc (3) in the circumferential direction. One of the tab connecting areas (31) is provided with a cap connecting area (32).

5. The cylindrical lithium-ion battery structure of claim 3 or 4, wherein: The tab (111) and the positive current collector disc (3) are connected by laser welding.

6. A cylindrical lithium-ion battery structure comprising a positive electrode sheet (1), a negative electrode sheet (2), a separator layer, and a cap, the separator layer being provided between the positive electrode sheet (1) and the negative electrode sheet (2), the positive electrode sheet (1), the separator layer, and the negative electrode sheet (2) being wound to form a jelly-roll assembly (4), characterized in that: The upper edge of the positive electrode plate (1) is provided with at least two tabs, and each tab is connected with a cap after welding.

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